Rant about handwriting copy (10)
I believe the answer is:
transcript
'copy' is the definition.
('transcript' can be a synonym of 'copy')
'rant about handwriting' is the wordplay.
'about' indicates an anagram.
'handwriting' becomes 'script' ('script' can be a synonym of 'handwriting').
'rant' with letters rearranged gives 'tran'.
'tran'+'script'='TRANSCRIPT'
(Other definitions for transcript that I've seen before include "Written copy of, eg, a speech" , "Written version of speech" , "Written item originally in another medium" , "Written copy of the spoken word" , "Record" .)